The present invention relates generally to switching of electrical power supply, and, more particularly, to LED control system.
Light emitting diode (LED) as a light source has the advantage of lower power consumption and excellent shock resistance. Conventionally, LED light is merely turned on and off, without dimming function and cannot be adjusted to match the needs at different seasons and at different ambient light situations.
Silicon controlled rectifier (SCR) has been used to efficiently adjust light output of resistive incandescent light bulbs. However, the SCR cannot be adequately used with LED light bulbs, because LED light bulbs generally include a switching power supply, which may have hundreds or even thousands of pulses, i.e., current cut-off periods, per cycle of an alternating current (AC). Even if the current is not completely cut off at valleys of the pulses, the reduced current may not be able to sustain SCR's conduction and cause the SCR to unexpectedly shut off, especially when the LED light bulb is of lower power rating or being adjusted to lower power output. The SCR can only be turned back on by next trigger. As a result, the LED light may exhibit abnormal light output or blink.
As such, what is desired is a control system that can efficiently adjust LED light output.
The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting, embodiments illustrated in the drawings, wherein like reference numbers (if they occur in more than one view) designate the same elements. The invention may be better understood by reference to one or more of these drawings in combination with the description presented herein.